Intel Core 2 Extreme QX9650, formerly known as Yorkfield, is the first 45-nm desktop CPU from Intel, being a quad-core CPU running internally at 3 GHz and externally at 1,333 MHz, the same clock specs of Core 2 Extreme QX6850. QX9650, however, brings two novelties: the new SSE4 instruction set and a larger 12 MB L2 memory cache, making it the most high-end desktop CPU available today. Did these two new features improve the CPU performance? That is exactly we are going to find out.

Just to clarify, Penryn isn’t the codename of a specific processor, but the codename of Intel’s 45-nm manufacturing process. The codename for desktop CPUs using Penryn technology is Yorkfield. So you might see this CPU being referred by these two codenames.

In the table below we summarized all CPUs included in this review with their main specs. As we mentioned Core 2 Extreme QX9650 has exactly the same clock specs as Core 2 Extreme QX6850 – working internally at 3 GHz, which is obtained by multiplying its external clock by 9 – so we were very curious in comparing these two CPUs.

As you can see, this quad-core CPU continues to use two L2 caches, so its 12 MB L2 cache is in fact two 6 MB caches, the first one being shared between cores 1 & 2 and the second one being shared between cores 3 & 4. For a more detailed explanation on this subject please read our article Intel Quad-Core CPU Overview and Roadmap.

For the record, we always configured our DDR2-1066/PC2-8500 memories running at 1,066 MHz.

CPU

Cores

Internal Clock

External Clock

L2 Memory Cache

SSE4

Platform

TDP

Man. Tech.

Core 2 Extreme QX9650

4

3 GHz

1,333 MHz (333 MHz x 4)

6 MB x 2

Yes

Socket LGA775

130 W

45 nm

Core 2 Extreme QX6850

4

3 GHz

1,333 MHz (333 MHz x 4)

4 MB x 2

No

Socket LGA775

130 W

65 nm

Core 2 Extreme QX6700

4

2.66 GHz

1,066 MHz (266 MHz x 4)

4 MB x 2

No

Socket LGA775

130 W

65 nm

Core 2 Extreme X6800

2

2.93 GHz

1,066 MHz (266 MHz x 4)

4 MB

No

Socket LGA775

75 W

65 nm

Core 2 Duo E6750

2

2.66 GHz

1,333 MHz (333 MHz x 4)

4 MB

No

Socket LGA775

65 W

65 nm

Core 2 Duo E6700

2

2.66 GHz

1,066 MHz (266 MHz x 4)

4 MB

No

Socket LGA775

65 W

65 nm

Pentium 4 550

1

3.4 GHz

800 MHz (200 MHz x 4)

1 MB

No

Socket LGA775

115 W

90 nm

TDP, Thermal Design Power, is how much power the CPU dissipates, meaning that you must match the CPU with a cooler capable of dissipating that amount of power.